A 13-year-old boy and a 15-year-old boy have been shot in two separate incidents in north-west London, police have said.

The shootings occurred within minutes of each other and in close proximity in Harrow on Sunday. Both boys suffered head injuries but neither was thought to be in a life-threatening condition, police said.

Officers were first called at 1.17pm to High Street, Wealdstone, to reports of a person having been shot.

A police spokesman said: “At the scene a 15-year-old boy suffering from a gunshot wound was treated by London ambulance service (LAS) before being taken to a central London hospital for treatment. His injuries are still being assessed – we await details of these and his condition.”

At 1.19pm, LAS alerted police to reports of a second boy with gunshot wounds at a different location in Wealdstone.

A 13-year-old boy was treated at the scene before being taken to a west London hospital where he remains. The spokesman said police were also awaiting details of his injuries and his condition.

The younger boy was originally reported to be 12, but a Scotland Yard spokeswoman later said he was 13 and had suffered a shotgun pellet wound to the head. Asked if the incidents were linked, she said that was one line of inquiry.

No arrests have yet been made and no firearms have been recovered.

A local shopkeeper said one of the victims, who had been shot near their shop, was lucky to be alive and they believed a bullet grazed the back of the boy’s head.

The manager of another nearby shop, who did not wish to give his name, said he was passing by on his lunch break and saw people gathered around a black male on the ground outside Specsavers.

He said: “He was holding his head down. I could not see his face but could see his white T-shirt was proper covered in blood. He was sitting calmly as the paramedics were looking after him.”

He described Wealdstone as a “kind of rough area and it can be a bit aggressive”.

On Sunday afternoon, Palmerston Road, just off Wealdstone High Street, was blocked off with police tape and attended by uniformed officers.

A grey Adidas sweatshirt with bloodstains on the hood lay crumpled on the ground outside Specsavers with a police exhibit number. A green first aid bag could also be seen behind the cordon as forensic officers took photographs and passersby were diverted from the scene.